Posted: Thu Mar 05, 2015 11:18 am Post subject: strange grinding noise, only heard at idle, 2007 3.5 flex
Hoping you can help me diagnose a strange noise I just started hearing in my 2007 Impala. Details follow:
car has approx 115000 on it.
About 2 days ago, I started hearing a strange grinding noise, but only at idle
Only happens when the car is warm (needle about 1/4 up on the water temp gauge)
As soon as I give it any gas, noise goes away.
Happens in park, neutral, and drive
When I listen to it with the hood up, it sounds like it's coming from the driver's side of the block on the lower side.
Sound kind of reminds me of the ABS grinding noise, but obviously it's not the ABS.
All fluids are full and look good, car runs and drives fine, although I think the throttle body need cleaning again. (got the "engine power reduced" message a couple days ago, went away after parking and restarting later, hasn't come back)
Noise is fairly loud, can be heard in the cabin of the car at road speeds
Am planning to tear apart throttle body and clean this weekend, but want some advice as to what else I should be looking at. Water pump? Power steering pump?
Posted: Fri Mar 06, 2015 11:55 am Post subject: Re: strange grinding noise, only heard at idle, 2007 3.5 fle
This morning, when I get in and go to start the car, I now hear that same noise when I turn the key to "run" but not all the way to start. That's when the fuel system pressurizes right? Or does the power steering pressurize when the switch is turned to "run" as well?
Yes, the fuel pump pressurizes for two seconds when you turn the key to on or acc. Unless the 2006+ has electric power steering, the power steering pump won't start running until the engine starts and the serpentine belt starts turning.
_________________ 2001 Galaxy Silver 9C1 w/ L67 and 4T65E-HD...and a few other mods.
Problem found: throttle body gears were stripped. Noise was high speed flutter in the throttle body when it was "hunting" for proper idle position but couldn't find it due to stripped teeth. Ordered new throttle body off Amazon for about $140. Gears don't appear to be replaceable. Wish they'd make these gears a little tougher.
Thanks for the help folks!
Yes, the fuel pump pressurizes for two seconds when you turn the key to on or acc. Unless the 2006+ has electric power steering, the power steering pump won't start running until the engine starts and the serpentine belt
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